--- qemu-kvm-0.11.0~rc2.orig/block/raw-posix.c
+++ qemu-kvm-0.11.0~rc2/block/raw-posix.c
@@ -867,7 +867,12 @@
     if (fd < 0) {
         result = -errno;
     } else {
-        if (ftruncate(fd, total_size * 512) != 0) {
+        struct stat stat;
+        if (!fstat(fd,&stat)) {
+          result = -errno;
+        }
+        if ((stat.st_mode & S_IFREG) && 
+            (ftruncate(fd, total_size * 512) != 0)) {
             result = -errno;
         }
         if (close(fd) != 0) {